A standard conveyor of this type has track-guided trucks which travel along a track network provided with switch points at which the trucks can be shunted off to branch tracks, or to loading or unloading stations. Each track carries a target code that is set according to the intended destination of the truck and each switch point is provided with a device that can read these codes. When a reader determines based on the code of an arriving truck that this truck should be switched to a branch track or a station, it appropriately operates the respective switch. The network invariably includes at least one endless main track about which the trucks travel until they are picked off at a switch point. Such arrangements are described in U.S. Pat. Nos. 3,340,821 and 3,502,038. In such conveyors, the target codes consist of one or more electromagnets arranged on the conveyor truck and settable in binary fashion to form the desired destination code.
Such conveyor installations function well, however it is not possible to monitor the operation situation, for instance to establish whether a certain truck really reached its target station, according to the initial setting. Furthermore if, for instance, a destination code is set that corresponds to no existing destination, the respective truck will simply continue to move around the loop and, in effect, become lost.
On the other hand, modern conveyor installations are known, such as from European open application 164,302, which comprise a central control unit which not only makes it possible to monitor the travel of the truck towards its target station, but also insures a concurrent monitoring of the conveyor installation. In this case the trucks are provided with individual identification codes which are also read and transmitted to the central control unit. In the central control unit both codes are processed and serve for the control of the switch points and the monitoring of the conveyor installation. Such control equipment is not suitable for retrofitting to an existing conveyor installation of the above-mentioned kind.